Ruby/String/String Range

s = "hello"
s[2..3]           # "ll": characters 2 and 3
s[-3..-1]         # "llo": negative indexes work, too
s[0..0]           # "h": this Range includes one character index
s[0...0]          # "": this Range is empty
s[2..1]           # "": this Range is also empty
s[7..10]          # nil: this Range is outside the string bounds
s[-2..-1] = "p!"     # Replacement: s becomes "help!"
s[0...0] = "Please " # Insertion: s becomes "Please help!"
s[6..10] = ""        # Deletion: s becomes "Please!"

speaker = "This is a test. This is a test. This is a test. This is a test. This is a test. "
speaker[13..15]= "This is a test. " # => "the Third"
p speaker # => "King Richard the Third"

speaker = "this is a test, 2007"
speaker[", 2007"]= "III" # => "III"
p speaker

("aa".."ag").each { |x| puts x }
# aa
# ab
# ac
# ad
# ae
# af
# ag

string = "My first string"                   # => "My first string"
string[3, 5]                             # => "first"

s = "My kingdom for a string!"
s.slice(3,7)                        # => "kingdom"
s[3,7]                              # => "kingdom"
s[0,3]                              # => "My "
s[11, 5]                            # => "for a"
s[11, 17]                           # => "for a string!"

s = "My kingdom for a string!"
s[15...s.length]                   # => "a string!"